The long range goal of Project III is to develop and apply the technology of functional magnetic resonance imaging (FMRI) to the study of human motor control and learning. FMRI will be used to elucidate the neural mechanisms that support movement in neurologically intact subjects. Four specific aims will be addressed in the proposed five-year project. The first aim will determine the parametric relationships between the force, velocity, and duration of repetitive, single joint movements of the upper and lower extremities and the magnitude of MR signal change observed in the primary and secondary cortical motor systems. The information derived from these studies will provide important information for designing and interpreting subsequent experiments. The second aim will examine the somatotopic organization of the primary motor cortex, lateral premotor cortex, supplementary motor area, cingulate sulcus, and cerebellum by examining the spatial extent of the signal change from repetitive, single joint movements of the upper and lower extremities. The three experiments proposed for the third aim are derived from human cognitive theory and will map the neural systems associated with specific aspects of cognitive- motor processing, including (1) motor programming and control operations supporting heterogeneous and repetitive sequential movements, (2) the utilization of hierarchical representations of sequential movements, and (3) timing operations associated with movement. The fourth aim will map the changes in brain activation patterns associated with the acquisition and the retention of motor skills by mapping the early and late functional changes associated with motor sequence learning. The fourth aim will also investigate two key aspects of skill acquisition, perceptual-motor and visual-pattern processing, to determine how the brain implements these processes throughout the course of learning. The experiments in this project seek to explore fundamental questions of human brain organization using a new technology that has the potential to become an extremely powerful neuroscience tool. The ultimate goals of this project are to construct a detailed map of functional specialization within the brain systems involved in motor control and to achieve a more comprehensive understanding of the neural systems that regulate the performance, learning, and retention of motor skills. Results of these studies may eventually lead to novel experimental procedures for understanding the abnormal brain organization patterns associated with human movement disorders.